n = int(input())
s = input()
check = s.count("R")
q = s[:check]
print(q.count("W")) n = int(input()) n int(input()) int input() input s = input() s input() input check = s.count("R") check s.count("R") s.count s count "R" q = s[:check] q s[:check] s :check check print(q.count("W")) print q.count("W") q.count q count "W" n = int(input()) int(input()) n s = input() input() s check = s.count("R") s.count("R") check q = s[:check] s[:check] q
n = int(input())
s = input()
check = s.count("R")
q = s[:check]
print(q.count("W"))